Utilizing SVD and VMD for Denoising Non-Stationary Signals of Roller Bearings

In view of the fact that vibration signals of rolling bearings are much contaminated by noise in the early failure period, this paper presents a new denoising SVD-VMD method by combining singular value decomposition (SVD) and variational mode decomposition (VMD). SVD is used to determine the structure of the underlying model, which is referred to as signal and noise subspaces, and VMD is used to decompose the original signal into several band-limited modes. Then the effective components are selected from these modes to reconstruct the denoised signal according to the difference spectrum (DS) of singular values and kurtosis values. Simulated signals and experimental signals of roller bearing faults have been analyzed using this proposed method and compared with SVD-DS. The results demonstrate that the proposed method can effectively retain the useful signals and denoise the bearing signals in extremely noisy backgrounds.

Overexpression of Shinorhizobium Meliloti Flavohemoglobinefficiently Improved Cell Growth and Fatty Acid Biosynthesis in Oleaginous Fungus Mucor Circinelloides

Oxygen availability is a limiting factor for lipid biosynthesis in eukaryotic microorganisms. Two bacterial hemoglobins from Vitreoscilla sp. (VHb) and Shinorhizobium meliloti (SHb), which could deliver the oxygen to the respiratory chain to produce more ATP, were introduced into Mucor circinelloides to alleviate oxygen limitation, thereby improving cell growth and fatty acid production. VHb and SHb genes were integrated into the M. circinelloides MU402 genome through homologous recombination, and their protein expression was verified by carbon monoxide difference spectrum (CO-difference spectrum)analysis. SHb-expressing strain showed higher biomass than VHb-expressing strain. The biomass of the SHb-expressing strain was increased by about 50% and the total fatty acid (TFA) content was as high as 15.7% of the dry cell weight which was about 40% higher than that of the control strain in flask conditions. In the fermenter, the maximum biomass and TFA content was obtained in SHb-expressing strains, with the biomass being 12.1 g/L and the TFA being 21.1% of the dry cell weight. VHb and SHb expression also affected the fatty acid composition with the proportion of polyunsaturated fatty acids being increased. Over-expression of bacterial hemoglobins, especially SHb increased cell growth and TFA content in M. circinelloides at low and high aeration, suggesting that SHb is better than VHb in improving the fatty acid production in oleaginous microorganisms.

Homeopathic Potencies vary from each other with respect to relative proportions of free and bound water molecules

ABSTRACT Homeopathic potencies 12CH and above cross the Avogadro number, and as such do not contain any original drug molecules in their aqueous ethanol medium. It is thought H-bonded water structures preserved by ethanol carry the information of initial drug molecules. Potentized drugs show some differences with respect to their infrared (IR) absorption spectra. In a water-ethanol solution, free water molecules vary according the concentration of ethanol. In the present study the concentration of ethanol has been kept constant at 0.03 molar fraction in 6 different homeopathic potencies. To see whether different homeopathic potencies having fixed ethanol content show variation in free water molecules. Two potencies like 8CH and 32CH of three homeopathic drugs Natrum mur, Cantharis and Nux vomica were used in the study, and their ethanol concentration was kept fixed at 0.03 molar fraction. The control was considered to be aquous ethanol at the same concentration. Spectrum of pure water was also taken. Fourier transform infrared (FTIR) absorption spectra were obtained in the wave number region of 4000 – 2800 cm-1. The half-width at half-maximum was measured for each spectrum. The intensity of each spectrum was normalized at 3410 cm-1 close to the peak. The difference spectrum (absorbance of drug solution – absorbance of pure water) for each drug and the control was obtained. FTIR spectra showed variation in absorbance intensity on both the high and low frequency side of the O-H stretching band in different drugs as well as the control. The C-H stretching band of 2977 cm-1 also showed variation in intensity in different drugs. In the difference spectra the absorbance intensity at the dip at 3630 cm-1 varied in different drugs and the control. The decrease in intensity at 3630 cm-1 and subsequent rise in intensity at lower frequency region represent the level of free water molecules and strong alcoholic O-H band around 3250 cm-1, respectively. The drug and the control solutions show distinct variation in their FTIR spectra. The drugs have different levels of bound and free water molecules although their ethanol concentration is same. Keywords-Homeopathic potencies, FTIR spectra, free water molecules, intensity and difference spectrum.

Diagnosis of Gulf War Illness Using Laser-Induced Spectra Acquired from Blood Samples

Gulf War illness (GWI) is a chronic illness with no known validated biomarkers that affects the lives of hundreds of thousands of people. As a result, there is an urgent need for the development of an untargeted and unbiased method to distinguish GWI patients from non-GWI patients. We report on the application of laser-induced breakdown spectroscopy (LIBS) to distinguish blood plasma samples from a group of subjects with GWI and from subjects with chronic low back pain as controls. We initially obtained LIBS data from blood plasma samples of four GWI patients and four non-GWI patients. We used an analytical method based on taking the difference between a mean LIBS spectrum obtained with those of GWI patients from the mean LIBS spectrum of those of the control group, to generate a “difference” spectrum for our classification model. This model was cross-validated using different numbers of differential LIBS emission peaks. A subset of 17 of the 82 atomic and ionic transitions that provided 70% of correct diagnosis was selected test in a blinded fashion using 10 additional samples and was found to yield 90% classification accuracy, 100% sensitivity, and 83.3% specificity. Of the 17 atomic and ionic transitions, eight could be assigned unambiguously to species of Na, K, and Fe.

Research on the Noise Reduction Method of the Vibration Signal of the Hydrogenerator Unit Based on ITD-PE-SVD

Aiming at the problem that the vibration signals of the hydrogenerator unit are nonlinear and nonstationary and it is difficult to extract the signal features due to strong background noise and complex electromagnetic interference, this paper proposes a dual noise reduction method based on intrinsic time-scale decomposition (ITD) and permutation entropy (PE) combined with singular value decomposition (SVD). Firstly, the vibration signals are decomposed by ITD to obtain a series of PRC components, and the permutation entropy of each component is calculated. Secondly, according to the set permutation entropy threshold, the PRC components are selected for reconstruction to achieve a noise reduction effect. On this basis, SVD is carried out, and the appropriate reconstruction order is selected according to the position of the singular value difference spectrum mutation point for reconstruction, so as to achieve the secondary noise reduction effect. The proposed method is compared with the LMD-PE-SVD and EMD-PE-SVD dual noise reduction method by simulation, taking the correlation coefficient and signal-to-noise ratio to evaluate the noise reduction performance and finding that the ITD-PE-SVD noise reduction has good noise reduction and pulse effect. Furthermore, this method is applied to the analysis of the upper guide swing data in the X-direction and Y-direction of a unit in a hydropower station in China, and it is found that this method can effectively reduce noise and accurately extract signal features, thus determining the vibration cause, which is helpful to improve the turbine fault recognition rate.

Free water molecules and hydrogen bonding form the basis of variation in homeopathic potencies as revealed by vibrational spectroscopy

Objective: Using Fourier Transform Infrared spectroscopy (FTIR) we have demonstrated that homeopathic potencies of Natrum mur, Cantharis, Nux vomica and Sulphur show differences with respect to the number of free water molecules and strength of hydrogen bonding. The purpose of the present study is to confirm this phenomenon in three potencies of two more drugs Calcarea carb and Silicea. Design: The potencies used for each of the two drugs were 30cH, 200cH and 1000cH. The control was 90% ethanol as also the potentized drugs. The control, as well as the potencies, were diluted with distilled water to reduce the level of ethanol to 0.03 molar fraction in each of them. FTIR spectra of all the potentized drugs, control and sterile distilled water (reference water) were taken in the wave number region of 4000-2800 cm-1. The full width at half maximum (fwhm) of OH band was measured for each spectrum. The width was divided into two in the middle. The difference spectrum (absorbance of drug solution - absorbance of reference water) for each potency and the control was obtained after normalization of the spectrum at 3410 cm-1. One difference spectrum so obtained for a potency was subtracted from another to find out if there is a difference between two different potencies. Results: The half width half maximum (hwhm) in both the high and low-frequency sides of the OH band is far less narrow in potencies than in the control as compared to that in water. The difference spectra for different potencies show different levels of fall in intensity at the wave number region of dip at 3630 cm-1. The level of dip at 3630 cm-1 and subsequent rise in intensity in the lower frequency region represent the quantity of free water molecules and strong alcoholic OH bond around 3250 cm-1, respectively. The results of subtraction between two different potencies are not zero but have marked positive or negative values. Conclusion (i) Potencies have stronger intermolecular interactions and a higher number of chemical environments than the control, as revealed by the data on hwhm. (ii) The three potencies of each of the two drugs show distinct variation in the number of free water molecules and strength of hydrogen bonding. (iii) There exists both inter-drug and inter-potency variation as revealed by the difference spectra and results of subtraction between two difference spectra.

Retinal vibrations in bacteriorhodopsin are mechanically harmonic but electronically anharmonic: evidence from overtone and combination bands

Vibrations of the chromophore in the membrane protein bacteriorhodopsin (BR), a protonated Schiff base retinal, have been studied for decades, both by resonance Raman and by infrared (IR) difference spectroscopy. In spite the light-induced IR difference spectrum between the K intermediate (13-cis retinal) and the initial BR state (all-trans retinal) being first published almost 40 years ago, we present here unreported bands in the 2500 to 1800 cm-1 region. We show that the bands between 2500 and 2300 cm-1 originate from overtone and combination transitions of retinal C-C stretches. We assigned some of the newly reported bands below 2300 cm-1 to the combination of retinal C-C stretches with methyl rocks and with hydrogen-out-of-plane vibrations. Remarkably, experimental C-C overtone bands appeared at roughly twice the wavenumber of their fundamentals, with anharmonic mechanical constants ≤ 3.5 cm-1, and in some cases of ≈ 1 cm-1. Comparison of combination and fundamental bands indicates that most of the mechanical coupling constants are also very small. Despite the mechanical quasi-harmonicity of the C-C stretches, the area of their overtone bands was only ≈50 to ≈100 times smaller than of their fundamental bands. We concluded that electronic anharmonicity, the second mechanism giving intensity to overtone bands, must be particularly high for the retinal C-C stretches. We corroborated the assignments of negative bands in the K-BR difference spectrum by ab initio anharmonic spectral calculations of all-trans retinal in BR, which also reproduced reasonably well the small experimental anharmonic and coupling mechanical constants. Yet, and in spite accounting for both mechanical and electronic anharmonicities, the intensity of overtone C-C transitions was underestimated by a factor of 4 to 20, indicating room for improvement in state-of-the-art anharmonic vibrational calculations.

Effects of Efficient Expression of Vitreoscilla Hemoglobin on Production, Monosaccharide Composition, and Antioxidant Activity of Exopolysaccharides in Ganoderma lucidum

A Vitreoscilla hemoglobin (VHb) gene was efficiently expressed by the optimization of codons and intron addition in G. lucidum. Expression of the VHb gene was confirmed by genome PCR, quantitative real-time PCR and carbon monoxide (CO)-difference spectrum analysis in the transformant. The effects of the efficient expression of VHb gene on production, monosaccharide compostion, and antioxidant activity of G. lucidum exopolysaccharides were studied. The maximum production of exopolysaccharides in the VHb gene-bearing transformant was 1.63 g/L, which was 1.5-fold higher than expression in the wild-type strain. Efficient expression of the VHb gene did not change the monosaccharide composition or distribution of molecular weight, but it increased the mole percentage ratio of galactose and mannose in G. lucidum exopolysaccharide. Exopolysaccharides from the transformant had higher scavenging 2,2-diphenyl-1-picrylhydrazyl (DPPH) and hydroxyl (OH) radical capacity and reducing power than those from the wild-type strain. These results may be helpful for increasing production and application of exopolysaccharides produced by G. lucidum fermentation.

Hexabromocyclododecanes are dehalogenated by CYP168A1 from a Pseudomonas strain HS9

Hexabromocyclododecanes (HBCDs) are widely used brominated flame retardants, which cause antidiuretic hormone syndrome and even induce cancer. However, little information is available about the degrading mechanisms of HBCDs. In this study, genomic, proteomic analyses, RT-qPCR and gene knockout assays reveal that a cytochrome P450 encoding gene is responsible for the HBCD catabolism in Pseudomonas aeruginosa HS9. CO-difference spectrum of the enzyme CYP168A1 was matched to P450 character and proved by western blot analysis and UV-visible. We demonstrate that the reactions of debromination and hydrogenation are carried out one after another based on detection of the metabolites pentabromocyclododecanols (PBCDOHs), tetrabromocyclododecadiols (TBCDDOHs) and Br - iron. In the 18 O isotope experiments, PBCD 18 OHs were only detected in the H 2 18 O group, proving that the added oxygen is derived from H 2 O not from O 2 . This study elucidates the degrading mechanism of HBCDs by Pseudomonas . Importance Hexabromocyclododecanes (HBCDs) are environmental pollutants, which are wildly used in industry. In this study, we identified and characterized a novel key dehalogenase CYP168A1 responsible for the HBCDs degradation from a Pseudomonas aeruginosa strain HS9. This study provides new insights into understanding biodegradation of HBCDs.